The government had previously said the rioting killed 192 and injured 1,721 more.

On July 5 a peaceful protest by local Uighur residents turned violent after it was stopped by police.

Official reports said the Uighurs went on a rampage, smashing windows, burning cars and beating Han Chinese, the nation's dominant ethnic group, in the worst ethnic clashes to hit the region in decades.

Two days after the first rioting, vigilante groups of ethnic Han apparently took to the streets and attacked Uighurs.

Chinese authorities have now released a video said to be taken inside a mosque in Urumqi on July 13 - eight days after the worst clashes.

They say it shows Uighur men leaving the mosque armed with machetes, then trying to attack police.

Officers then shoot three of the men, killing two of them.

Protest's genesis

The initial protest was centred on calls for an investigation into the deaths of Uighur factory workers which occurred on June 25 during a fight with Han Chinese in the southern city of Shaoguan.

State media reported that two people died, but photos spread on the internet soon after apparently showed at least a half-dozen bodies of Uighurs, with Han Chinese standing over them, arms raised in victory.

Chinese authorities accused Rebiya Kadeer, a prominent US-based exiled Uighur activist, of inciting the unrest. They have not provided evidence, and Kadeer has denied it.

About 1,000 people, mostly Uighurs, have been detained in the resulting government crackdown.